From a3315cdcf6ca2714e563eb813b645e267ba2ea5a Mon Sep 17 00:00:00 2001
From: Jason Zaugg <jzaugg@gmail.com>
Date: Sat, 30 Jun 2012 09:13:05 +0200
Subject: SI-2807 Avoid catch all warning for Stable Id patterns

---
 .../scala/tools/nsc/typechecker/Typers.scala       |  5 ++--
 test/files/neg/catch-all.check                     | 12 ++++-----
 test/files/neg/catch-all.scala                     | 30 +++++++++++++++-------
 3 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index d251109dc4..25857773fe 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -4865,9 +4865,10 @@ trait Typers extends Modes with Adaptations with Tags {
 
           for (cdef <- catches1 if cdef.guard.isEmpty) {
             def warn(name: Name) = context.warning(cdef.pat.pos, s"This catches all Throwables. If this is really intended, use `case ${name.decoded} : Throwable` to clear this warning.")
+            def unbound(t: Tree) = t.symbol == null || t.symbol == NoSymbol
             cdef.pat match {
-              case Bind(name, Ident(_)) => warn(name)
-              case Ident(name)          => warn(name)
+              case Bind(name, i@Ident(_)) if unbound(i) => warn(name)
+              case i@Ident(name) if unbound(i)          => warn(name)
               case _ =>
             }
           }
diff --git a/test/files/neg/catch-all.check b/test/files/neg/catch-all.check
index ab3d28777d..62f895cc7e 100644
--- a/test/files/neg/catch-all.check
+++ b/test/files/neg/catch-all.check
@@ -1,10 +1,10 @@
 catch-all.scala:2: error: This catches all Throwables. If this is really intended, use `case _ : Throwable` to clear this warning.
-	try { "warn" } catch { case _ => }
-                                    ^
+  try { "warn" } catch { case _ => }
+                              ^
 catch-all.scala:4: error: This catches all Throwables. If this is really intended, use `case x : Throwable` to clear this warning.
-	try { "warn" } catch { case x => }
-                                    ^
+  try { "warn" } catch { case x => }
+                              ^
 catch-all.scala:6: error: This catches all Throwables. If this is really intended, use `case x : Throwable` to clear this warning.
-	try { "warn" } catch { case _: RuntimeException => ; case x => }
-                                                                  ^
+  try { "warn" } catch { case _: RuntimeException => ; case x => }
+                                                            ^
 three errors found
diff --git a/test/files/neg/catch-all.scala b/test/files/neg/catch-all.scala
index 35a6d7af91..c05be77044 100644
--- a/test/files/neg/catch-all.scala
+++ b/test/files/neg/catch-all.scala
@@ -1,19 +1,31 @@
 object CatchAll {
-	try { "warn" } catch { case _ => }
+  try { "warn" } catch { case _ => }
 
-	try { "warn" } catch { case x => }
+  try { "warn" } catch { case x => }
 
-	try { "warn" } catch { case _: RuntimeException => ; case x => }
+  try { "warn" } catch { case _: RuntimeException => ; case x => }
 
-	try { "okay" } catch { case _: Throwable => }
+  val t = T
 
-	try { "okay" } catch { case _: Exception => }
+  try { "okay" } catch { case T => }
 
-	try { "okay" } catch { case okay: Throwable => }
+  try { "okay" } catch { case `t` => }
 
-	try { "okay" } catch { case okay: Exception => }
+  try { "okay" } catch { case x @ T => }
 
-	try { "okay" } catch { case _ if "".isEmpty => }
+  try { "okay" } catch { case x @ `t` => }
 
-	"okay" match { case _ => "" }
+  try { "okay" } catch { case _: Throwable => }
+
+  try { "okay" } catch { case _: Exception => }
+
+  try { "okay" } catch { case okay: Throwable => }
+
+  try { "okay" } catch { case okay: Exception => }
+
+  try { "okay" } catch { case _ if "".isEmpty => }
+
+  "okay" match { case _ => "" }
 }
+
+object T extends Throwable
-- 
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